You're 100% right, in addition of being an outstanding and amazing ice dance couple, both Gaby and Guillaume are great people... definitely great people...
Gaby and Guillaume achieved fantastic performances the last 4 years. Their next goals are Europeans and Worlds and of course Bejing 2022. In any case, they want to be themselves hence promoting their own vision of ice dance, based on contemporary choreographies, softness, class and this very specific ability to pass on emotions to the public. I think they want to move on to new stuff while staying themselves. They wanted to keep on performing the Ed Sheeran SD during the French tour and not the Moonlight Sonata FD. That was a clear sign. Ed Sheeran is about fun and joy while Moonlight Sonata is more about drama. Moving forward, I think they want less drama and more fun in their music, choreographies and programs.
Gaby and Guillaume are exploring any possible options as the beginning of a new Olympic cycle is always the right time to do so. Gaby and Guillaume love challenges, they want/need their coaches to challenge them, they even challenge themselves (like they did in 2016/17) but they also challenge their coaches as well!
They are not interested in being part of a sort of ice dancers manufactory, confined in a kind of routine, without coaches pushing them to take up new challenges, which means the coaches have to spend time and be talented enough to invent these new challenges.
Gaby and Guillaume could leave Gadbois if they can find elsewhere a very strong skating coaching team, fitness coaching team, artistic coaching team, dance coaching team and mental coaching team or at least being confident there's a clear perspective to get that in a short term.
At this point, I guess Gaby and Guillaume would stay in Gadbois but with a different coaching team setup, meaning with new choreographers involved in their programs (like Chris Dean for the OG SD). Given many couples moved or are about to move to Gadbois, I think they may need to extend their skating training to other rinks than Gadbois.